Hey Zombie thumbs! The "Hoplite" Shield is called an Aspis, a round convex shield with an armband called a porpax. The term "Hoplite" is a term used to refer to a fully equipped man, meaning a man with full armor weapons and his aspis shield. The debate over the overhand grip in dense formations arises from interpretations of vase paintings and experimental archaeologists. When re-enactors have tried to duplicate dense formations they say the ability to wield the spear underhanded is impaired and when the pressing or Othismos phase of battle is duplicated supposedly the buttspike (called a sauroter) tends to impale the wielder in the thigh or jabs the guy behind you. Indeed most reenactors tell stories and have scars in their right thighs and will tell you all about failed attempts. Personally I think there is a hint in the language the Greeks used of the phases of combat itself, prior to the "Pushing" phase there is a phase referred to as "Doratismos" or spear fencing. My theory is that this phase was a more open formation with underhanded spears with the goal in mind of attritting the opposing formation. When the commander of that formation believed they had the advantage they closed up the formation, brought spears overhead and tried to break the enemy formation by advancing and shoving. An interesting little side note, apparently modern engineers have figured out that during riots and panicked crowd situations it takes 8 human beings pushing forward for the crushing effect to become lethal to those upfront. A typical hoplite formation was exactly 8 ranks deep. One of the theories behind the convex shape of an Aspis shield is to create a cavity to protect a human chest cavity from being fatally collapsed.

This is a really easy solution. Acts of god are fine and can run concurrent with a typical strategy game and It is not necessary to build an entire game around that disruption. If you want acts of God in your game you simply have to introduce a means of gauging probabilities for those disasters in the future. Oracles, Sibyls and prophetic predictions have been common throughout history and fits a historical context without making it fantastic. Most of history have been steeped in superstitious beliefs and leaders throughout that history have consulted with diviners who were supposedly conduits with the Gods/God. You want a more modern setting simply turn them into advisors who are aware of impending disasters.
Mechanically all you have to do is consult these advisors as to their prophetic predictions. They would give some indication about potential incoming disruptive events that the player would be able to account for. How vague you wanted to make these can be easily tied to either a skill level of that advisor/oracle or tied to information gathering units. I'll use an example, of which there are plenty, Nero consulted Delphi after killing his own mother "Your presence here outrages the god you seek. Go back, matricide! The number 73 marks the hour of your downfall!". Nero interpreted this as predicting a long reign as he in expected to live until 73, instead Galba's revolt ended Nero's reign. Galba was 73 years old.
How steeped the decision making process then becomes is a matter of choice for the player. Remember that the predictions become probabilities rather then historical inevitabilities so the player decides how much to listen to them.